In the experimental research on the impact of 10-35kV wildfire and tree line faults on transmission lines, it was found that arc grounding overvoltage were generated. This paper studies and analyzes the mechanism of overvoltage generation. The research analyzes the three-phase voltage and zero sequence voltage caused by overvoltage. Variation characteristics, when resonance occurs, the random voltage of one phase is less than the voltage of the other two phases, and the magnitude of this voltage is determined by the neutral point displacement voltage; the moment of arc overvoltage will cause the amplitude of the zero sequence voltage and the non-fault phase voltage to be rapid within 0.6ms, the fault phase voltage is lower than the rated voltage, and presents a power frequency cycle change trend. Modeling and simulation were carried out by PSCAD/EMPTC simulation software, and the variation characteristics of arc overvoltage between metal and high resistance grounding were verified.

transmission lines;arc grounding overvoltage;zero sequence voltage;Variation characteristics